YouTube uses a flag system that allows users to report videos as inappropriate which according to YouTube can happen by any violation of the YouTube terms of service. Flags are then added automatically to videos even if they are not inappropriate, as it is an automated process.
A flagged video will be reviewed by an administrator who has numerous options at hand including setting the flag for age verification which requires users to login before they can view the video. Age verification is pretty basic and anyone who cheated on his birthday can watch the video after logging in. Cheating in this regard means entering a different birth day during registration which raises the age to 18 or above.
The message that gets displayed when a user who is not logged in loads a video with age verification is the following: “This video or group may contain content that is inappropriate for some users, as flagged by YouTube’s user community. To view this video or group, please verify you are 18 or older by signing in or signing up.”
Numerous ways to bypass the age verification check have been posted in the past which included using caches and proxies. The Firefox extension You Old Enough provides users with another way. The experimental add-on will check if the video on YouTube is flagged for age verification and open it immediately in a popup window.

This means that it is possible to watch all videos on YouTube that require age verification without having to login to the system. That’s good news for privacy sensible users who do not want to hand over their usage data to data mining Google.
Update: The Firefox extension has been discontinued. Users can instead download the Greasemonkey userscript Bypass YouTube age verification which can also be used to skip age verification checks on YouTube.
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I am 17 but I always put in some different date to make myself ‘older’. It gets useful every where, from Youtube to Adsense. I’m waiting for 7th January 2009.
Oh yes ;D I am Old Enough~ What a great extension. I am sixteen right after 6th October 2008. I usually set a real age for my account. So… I never was able to see these flagged video on youTube.
I’m 54 but I love saying I’m barely 18 !!!
Lame. How difficult is it to rewrite the blocked link “/watch?v=lzXQmOBWEuc” to “/v/lzXQmOBWEuc”? These kind of extensions just take up space.
@Joseph:
This bypass method seems to have been blocked/fixed by youtube already.
WHERE DO I DOWNLOAD THIS FOR INTERNET EXPLORER 8
i m a 42 yrs old man so not worry abt us
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